基于燃烧理论的大气污染物排放浓度折算方法研究

Study of the air pollutants emission concentration conversion methods based on combustion theory

为了解决不同条件下,大气污染物排放浓度折算方法的适用问题,本文统计了44项国家大气污染物排放标准采用的共计3种折算方法,基于燃烧理论对各折算方法及其适用性进行了计算推导和适用性分析,结果表明:1)过量空气系数折算法是建立在假定燃料特征下的简化方法,只适用于燃料成分因数χ值接近0的燃料,进一步研究显示,燃煤、生物质、垃圾等常见固体燃料的χ值介于-0.04~0之间,燃油的χ值介于-0.07~-0.06之间,矿井气的χ值仅为-0.01左右,沼气、油田伴生气、天然气、焦炉煤气的χ值约为-0.06~0.11,发生炉煤气、转炉煤气、高炉煤气的χ值分别达到0.47、0.48、1.35不适用过量空气系数折算法;2)烟气含氧量折算法通过燃烧计算模型严密推导得到,不受燃料限制,适用于烟气中CO等可燃气体残余量较少(建议低于1000ppm)的燃烧条件;3)排气量折算法直接通过排气量进行折算,适用于单位产品实际排气量高于规定的基准排气量的情况,且多为直接通过排气筒向环境排放(无燃烧)的场合。

In order to study the applicability of the conversion method for air pollutant emission concentration under different conditions,forty-four national air pollutant emission standards and three conversion methods are compared,with the formula derivation and applicability analysis based on combustion theory.The results are as follows:1)The conversion method based on excess air ratio is a simplified calculation method with hypothetical condition,and it’s only suitable for the fuels whose fuel component factor is close to zero.Further research shows that χ value of coal,biomass,garbage and other common solid fuel are between 0.04~0;χ value of various oils are between-0.07~-0.06;χvalue of mine gas is only about 0.01;χvalue of biogas,oilfield associated gas,natural gas,and coke oven gas are about 0.06~0.11;χ value of furnace gas,converter gas,and blast furnace gas are 0.47,0.48,1.35 that do not apply to conversion method respectively.2)The conversion method based on flue gas oxygen content is derived from the combustion calculation model,which is not limited by fuel type and is suitable for the condition that residual amount of combustible gases such as CO in flue gas is negligible(below 1000 ppm).3)The conversion method based on exhaust volume is mainly used in the case that the actual exhaust volume per unit product is more than the standard exhaust volume,and the gas is discharged directly through the stack(without combustion).